Work completed within the past two years has shown, for several teleost fish species, that probability of survival is correlated with the configuration of central nervous decussations. Different decussation patterns (viz., whether the right or left member of a pair of sister pathways occupies the dorsal or ventral position as these pathways cross the midline) are associated with differences in lateral asymmetries in the size of otherwise mirror-symmetric neural structures. This earlier work has also shown that different patterns of neural asymmetry are associated with differences in behavioral and metabolic characteristics. Indirect evidence suggests that the behavioral and, to a lesser extent, the metabolic correlates of decussation geometry underlie the differences in survival rate. During the next year attention will be focused on four unresolved questions: (1) How do individuals with one pattern of behavioral biases interact with individuals that have similar or different behavioral biases? (2) What are the relationships between neural asymmetries and somatic asymmetries? (3) Do behavioral biases result from neural asymmetries, from somatic asymmetries or from some combination of the two? (4) What underlies the differential development of the two sides of the nervous system?